H12-891_V1.0 Exam Dumps - Huawei HCIE-Datacom Questions and Answers

BGP in Huawei SD-WAN

Huawei SD-WAN uses BGP (Border Gateway Protocol) as the primary routing protocol to exchange VPN routes between Customer Premises Equipment (CPEs) and the controller.

✅ Why BGP is Used in SD-WAN?

Scalability: BGP can handle a large number of VPN routes.

Policy-Based Routing: BGP allows traffic engineering and policy control across SD-WAN tunnels.

Multiprotocol Support: Huawei SD-WAN uses MP-BGP to exchange IPv4, IPv6, and VPNv4 routes.

Comprehensive and Detailed In-Depth Explanation:

The free mobility function in iMaster NCE-Campus allows users to maintain consistent security policies regardless of their physical location within the campus network. To correctly implement this function, the administrator must:

A. Define security groups: Group users and devices based on roles or functions.

B. Deliver the inter-group policy: Apply policies that define how different security groups interact.

C. Deploy a policy control matrix: Establish a matrix that specifies the access control policies between security groups.

D. Select the policy enforcement point: Choose devices or interfaces where policies are enforced, such as switches or routers.

All four steps are crucial for achieving dynamic policy enforcement in a virtualized and mobility-oriented campus network.

Huawei iMaster NCE-Campus as an Authentication Relay Agent

Huawei iMaster NCE-Campus can act as a relay agent for authentication services, forwarding authentication requests between users and authentication servers (e.g., RADIUS, LDAP).

✅ B. User Authentication

Validates user credentials before granting network access.

Supports 802.1X, Portal, MAC, and RADIUS authentication.

✅ C. User Analysis

Analyzes user behavior and access patterns to optimize security and network policies.

✅ D. Marketing

Provides customized authentication portals with advertisements and promotional messages.

Incorrect Answer:

❌ A. User Accounting – Accounting is handled by the authentication server (e.g., RADIUS), not the relay agent.

Reference from Huawei HCIE-Datacom Documentation:

Huawei iMaster NCE-Campus Authentication Guide – Relay Agent Functions

HCIE-Datacom Study Material – User Authentication and Analysis in CloudCampus

IS-IS (Intermediate System to Intermediate System) protocol has a limit on the size of Link-State PDUs (LSPs).

Why Fragmentation?

LSPs contain routing and topology information.

If the LSP exceeds the maximum size, fragmentation allows the device to store and forward more routes by breaking them into smaller LSPs.

Key Point: IS-IS fragmentation is essential in large-scale networks where routing tables grow beyond the default LSP size limit.

✅ Reference: Huawei HCIE-Datacom Guide - IS-IS Protocol and Route Scaling

In Huawei ' s SRv6 instruction naming system, each letter keyword represents a specific forwarding behavior:

X (Cross): Forwards packets via specified Layer 3 interfaces → ✅

M (MAC): Searches Layer 2 forwarding table for broadcast/multicast, not unicast → ❌

V (VPN): Searches the VPN routing table (VRF) for forwarding → ✅

T (Table): Searches a specific routing table (e.g., user-defined) → ✅

Correct answers: A, C, D

Congestion Avoidance in Networking

Congestion avoidance mechanisms prevent packet loss and delay by managing queues before congestion occurs.

Common Congestion Avoidance Techniques:

Weighted Random Early Detection (WRED) – Randomly drops low-priority packets before congestion builds up.

Explicit Congestion Notification (ECN) – Marks packets instead of dropping them to signal congestion.

Queue Management – Techniques like priority queuing (PQ) and weighted fair queuing (WFQ) help prevent congestion.

Reference from Huawei HCIE-Datacom Documentation:

Huawei QoS Configuration Guide – Congestion Avoidance Technologies

HCIE-Datacom Study Material – Traffic Management and Queue Optimization

The free mobility solution in Huawei iMaster NCE-Campus allows:

Centralized policy management via the controller

Security group-based policies, decoupled from IPs/VLANs

Automatic policy delivery, no need to configure repeatedly per device

Dynamic mapping of users and IPs via security group subscriptions

Exact Extract - Huawei iMaster NCE-Campus Solution White Paper:

“Free mobility uses security groups and centralized control to enable consistent policy enforcement, avoiding repetitive configurations and simplifying policy management.”

Comprehensive and Detailed Explanation:

✔ gRPC supports four types of RPCs:

Unary RPC → Client sends one request, server responds once.

Server streaming RPC → Server sends multiple responses.

Client streaming RPC → Client sends multiple requests.

Bidirectional streaming RPC → Both sides exchange multiple messages.

✔ Why B and C Are Incorrect:

❌ (B) Incorrect → The method rpc dataPublish(stream serviceArgs) returns(stream serviceArgs) {} violates gRPC syntax.

❌ (C) Incorrect → rpc stream LotsOfGreetings(HelloRequest) returns (HelloResponse) {} contains incorrect stream positioning.

???? Reference: Huawei HCIE Datacom – gRPC API and Streaming Mechanisms

✔ TI-LFA (Topology Independent Loop-Free Alternate) is an enhanced Fast Reroute (FRR) mechanism used in SR-MPLS networks.

✔ How TI-LFA Works:

A virtual node is created, aggregating multiple route advertisements.

Backup paths are precomputed using Segment Routing (SR) SIDs.

When a link failure occurs, traffic is rerouted in < 50ms without waiting for IGP convergence.

???? Reference: Huawei HCIE Datacom – TI-LFA and SR-MPLS TE Protection